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Environmental wireless sensor network (EWSN) systems are deployed in potentially harsh and remote environments where inevitable node and communication failures must be tolerated. LUSTER---Light Under Shrub Thicket for Environmental Research---is a system that meets the challenges of EWSNs using a hierarchical architecture that includes distributed reliable(More)
—One of the primary requirements in many cyber-physical systems (CPS) is that the sensor data derived from the physical world should be disseminated in a timely and reliable manner to all interested collaborative entities. However, providing reliable and timely data dissemination services is especially challenging for CPS since they often operate in highly(More)
Recently, cheap and large capacity non-volatile memory such as flash memory is rapidly replacing disks in embedded systems. While the access time of flash memory is highly predictable, deadline misses may occur if data objects in flash memory are not properly managed in real-time embedded databases. Buffer cache can be used to mitigate this problem.(More)
QeDB is a database for data-intensive real-time applications running on flash memory-based embedded systems. Currently , databases for embedded systems are best effort, providing no guarantees on its timeliness and data freshness. Moreover , the existing real-time database (RTDB) technology can not be applied to these embedded databases since they(More)
—QeDB (Quality-aware real-time Embedded DataBase) is a database for data-intensive real-time applications running on embedded devices. Currently, databases for embedded systems are best effort, providing no guarantees on their timeliness and data freshness. Existing real-time database (RTDB) technology cannot be applied to these embedded databases since it(More)
Achieving situation awareness is especially challenging for real-time data stream applications because they i) operate on continuous unbounded streams of data, and ii) have inherent real-time requirements. In this paper we showed how formal data stream modeling and analysis can be used to better understand stream behavior, evaluate query costs, and improve(More)
Even though real-time data access to remote sensor data is desirable for many WSN applications, collecting remote data reliably from a WSN is a challenging task since many components of the WSN are subject to harsh elements of nature. A deployed system's performance and lifetime can be impaired if this harsh environment of the deployment site is not(More)
—It is a challenging task to provide timely access to global data from sensors in large-scale sensor network applications. Current data storage architectures for sensor networks have to make trade-offs between timeliness and scalability. PRIDE is a data abstraction layer for 2-tier sensor networks, which enables timely access to global data from the sensor(More)